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(N0 Model) J. H. PENDLETON.

DRILL,

No. 319,614. Patented June 9, 1885.

UNITED STATES JOHN H. PENDLETON, OF BROOKLYN,

ATENT rrIcE.

NEW YORK, ASSIGNOR TO HIMSELF,

ALEXANDER H. TIERS AND ooRNELIuS TIERS, BOTH OF MADISON, NEW JERSEY, WILLIAM G. STEPHENS, or oIIIoAoo, ILLINOIS, AND JOSEPH B. DIOKSON, or MORRISTOWN, NEW JERSEY.

DRILL.

SPECIFICATION forming part of Letters Patent No. 319,614:, dated June 9, 1885.

Application filed September 4, 1883. Renewed November 24, 1884. (No model.)

T at whom it may concern:

Be it known that I, J OHN H. PENDLEToN, of Brooklyn, in the county of Kings and State of New York, have invented an Improvement in Drills, of which the following is a specification.

In Letters Patent No. 283,509, granted to me, a drill is shown in which there are longitudinal grooves extending from the cuttingedge and opening into spiral grooves on the body of the drill.

My present invention is specially intended as an improvement upon the aforesaid drill; and it relates to a drill in which the longitudinal grooves are each formed with a flat face at the end of which is the cutting-edge. The flat faces in the two grooves are parallel to each other and extend to points in line with but at each side of the axis of the drill. The bottom of each groove is Vshaped, and the surfaces are inclined to each other at an obtuse angle, and the surface of each groove that is not in line with the cutting-edge is rounding, so as to form a trough for the reception and forward ing of the chips from one end to the other of the groove. The angle at the bottom of each groove forms a guide to the workman in grinding the tool, so that the cutting-edge may be straight and at an acute angle to the axis, and the back of the cuttingedge be sufficiently beveled not to rub upon the metal; hence the cut will be without unnecessary friction or strain upon the tool.

In the drawings, Figure 1 is an end view of 5 the drill, and Fig. 2 is a side view.

. The bottoms of the longitudinal grooves 11 a in the drill, when seen endwise, form obtuse angles 1 2 3, and from 3 to 4 the surfaces are curved or partially curved, as represented. The bottoms of the grooves at 2 2 are near but slightly at each side of the axis of the drill, so

as to retain the necessary strength. The portions 2 3 of the grooves are planes parallel to each other; so, also, the portions 1 2 are planes, the plane in one groove being parallel to that in the other, and the junctions of the planes along the line 2 become guides to the workman in sharpening the drill. The cutting end of the drill is conical; hence the cuttingedges at the ends of the planes 1 2 are Straight lines, but at an acute angle to the axis of the drill.

The grooves 01. a may be straight throughout their length, or they may be at a slight inclination or twist to the axis, or they may terniinate with spiral rearward extensions, as in my aforesaid patent.

I claim as my invention The drill having grooves at opposite sides, the bottoms of the grooves being planes 1 2 and 3 2, uniting at 2 near to but at each side of the axis of the drill, the portions 3 4. of the grooves having curved or partially curved surfaces, substantially as set forth.

Signed by me this 1st day of September, A. 6 5 D. 1883.

J. H. PENDLETON. iVitnessesz GEO. T. PINoKNEY, WILLIAM G. Mo'r'r. 

